/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.jasper.servlet;

import org.apache.jasper.JasperException;
import org.apache.jasper.runtime.ExceptionUtils;

import javax.servlet.*;
import javax.servlet.FilterRegistration.Dynamic;
import javax.servlet.descriptor.JspConfigDescriptor;
import java.io.File;
import java.io.InputStream;
import java.io.PrintWriter;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

/**
 * Simple <code>ServletContext</code> implementation without
 * HTTP-specific methods.
 *
 * @author Peter Rossbach (pr@webapp.de)
 */

public class JspCServletContext implements ServletContext {


	// ----------------------------------------------------- Instance Variables

	/**
	 * Servlet context initialization parameters.
	 */
	private final ConcurrentMap<String, String> myParameters =
			new ConcurrentHashMap<String, String>();
	/**
	 * Web application class loader.
	 */
	private final ClassLoader loader;
	/**
	 * Servlet context attributes.
	 */
	protected Hashtable<String, Object> myAttributes;
	/**
	 * The log writer we will write log messages to.
	 */
	protected PrintWriter myLogWriter;
	/**
	 * The base URL (document root) for this context.
	 */
	protected URL myResourceBaseURL;


	// ----------------------------------------------------------- Constructors

	/**
	 * Create a new instance of this ServletContext implementation.
	 *
	 * @param aLogWriter       PrintWriter which is used for <code>log()</code> calls
	 * @param aResourceBaseURL Resource base URL
	 */
	public JspCServletContext(PrintWriter aLogWriter, URL aResourceBaseURL, ClassLoader classLoader)
			throws JasperException {

		myAttributes = new Hashtable<String, Object>();
		myLogWriter = aLogWriter;
		myResourceBaseURL = aResourceBaseURL;
		this.loader = classLoader;

	}


	// --------------------------------------------------------- Public Methods

	/**
	 * Return the specified context attribute, if any.
	 *
	 * @param name Name of the requested attribute
	 */
	@Override
	public Object getAttribute(String name) {

		return (myAttributes.get(name));

	}

	/**
	 * Return an enumeration of context attribute names.
	 */
	@Override
	public Enumeration<String> getAttributeNames() {

		return (myAttributes.keys());

	}

	/**
	 * Return the servlet context for the specified path.
	 *
	 * @param uripath Server-relative path starting with '/'
	 */
	@Override
	public ServletContext getContext(String uripath) {

		return (null);

	}

	/**
	 * Return the context path.
	 */
	@Override
	public String getContextPath() {

		return (null);

	}

	/**
	 * Return the specified context initialization parameter.
	 *
	 * @param name Name of the requested parameter
	 */
	@Override
	public String getInitParameter(String name) {
		return myParameters.get(name);
	}

	/**
	 * Return an enumeration of the names of context initialization
	 * parameters.
	 */
	@Override
	public Enumeration<String> getInitParameterNames() {
		return Collections.enumeration(myParameters.keySet());
	}

	/**
	 * Return the Servlet API major version number.
	 */
	@Override
	public int getMajorVersion() {

		return (3);

	}

	/**
	 * Return the MIME type for the specified filename.
	 *
	 * @param file Filename whose MIME type is requested
	 */
	@Override
	public String getMimeType(String file) {

		return (null);

	}

	/**
	 * Return the Servlet API minor version number.
	 */
	@Override
	public int getMinorVersion() {

		return (0);

	}

	/**
	 * Return a request dispatcher for the specified servlet name.
	 *
	 * @param name Name of the requested servlet
	 */
	@Override
	public RequestDispatcher getNamedDispatcher(String name) {

		return (null);

	}

	/**
	 * Return the real path for the specified context-relative
	 * virtual path.
	 *
	 * @param path The context-relative virtual path to resolve
	 */
	@Override
	public String getRealPath(String path) {

		if (!myResourceBaseURL.getProtocol().equals("file"))
			return null;
		if (!path.startsWith("/"))
			return null;
		try {
			File f = new File(getResource(path).toURI());
			return f.getAbsolutePath();
		} catch (Throwable t) {
			ExceptionUtils.handleThrowable(t);
			return null;
		}
	}

	/**
	 * Return a request dispatcher for the specified context-relative path.
	 *
	 * @param path Context-relative path for which to acquire a dispatcher
	 */
	@Override
	public RequestDispatcher getRequestDispatcher(String path) {

		return (null);

	}

	/**
	 * Return a URL object of a resource that is mapped to the
	 * specified context-relative path.
	 *
	 * @param path Context-relative path of the desired resource
	 * @throws MalformedURLException if the resource path is
	 *                               not properly formed
	 */
	@Override
	public URL getResource(String path) throws MalformedURLException {

		if (!path.startsWith("/"))
			throw new MalformedURLException("Path '" + path +
					"' does not start with '/'");
		URL url = new URL(myResourceBaseURL, path.substring(1));
		InputStream is = null;
		try {
			is = url.openStream();
		} catch (Throwable t) {
			ExceptionUtils.handleThrowable(t);
			url = null;
		} finally {
			if (is != null) {
				try {
					is.close();
				} catch (Throwable t2) {
					ExceptionUtils.handleThrowable(t2);
				}
			}
		}
		return url;

	}

	/**
	 * Return an InputStream allowing access to the resource at the
	 * specified context-relative path.
	 *
	 * @param path Context-relative path of the desired resource
	 */
	@Override
	public InputStream getResourceAsStream(String path) {

		try {
			return (getResource(path).openStream());
		} catch (Throwable t) {
			ExceptionUtils.handleThrowable(t);
			return (null);
		}

	}

	/**
	 * Return the set of resource paths for the "directory" at the
	 * specified context path.
	 *
	 * @param path Context-relative base path
	 */
	@Override
	public Set<String> getResourcePaths(String path) {

		Set<String> thePaths = new HashSet<String>();
		if (!path.endsWith("/"))
			path += "/";
		String basePath = getRealPath(path);
		if (basePath == null)
			return (thePaths);
		File theBaseDir = new File(basePath);
		if (!theBaseDir.exists() || !theBaseDir.isDirectory())
			return (thePaths);
		String theFiles[] = theBaseDir.list();
		if (theFiles == null) {
			return thePaths;
		}
		for (int i = 0; i < theFiles.length; i++) {
			File testFile = new File(basePath + File.separator + theFiles[i]);
			if (testFile.isFile())
				thePaths.add(path + theFiles[i]);
			else if (testFile.isDirectory())
				thePaths.add(path + theFiles[i] + "/");
		}
		return (thePaths);

	}

	/**
	 * Return descriptive information about this server.
	 */
	@Override
	public String getServerInfo() {

		return ("JspCServletContext/1.0");

	}

	/**
	 * Return a null reference for the specified servlet name.
	 *
	 * @param name Name of the requested servlet
	 * @deprecated This method has been deprecated with no replacement
	 */
	@Override
	@Deprecated
	public Servlet getServlet(String name) throws ServletException {

		return (null);

	}

	/**
	 * Return the name of this servlet context.
	 */
	@Override
	public String getServletContextName() {

		return (getServerInfo());

	}

	/**
	 * Return an empty enumeration of servlet names.
	 *
	 * @deprecated This method has been deprecated with no replacement
	 */
	@Override
	@Deprecated
	public Enumeration<String> getServletNames() {

		return (new Vector<String>().elements());

	}

	/**
	 * Return an empty enumeration of servlets.
	 *
	 * @deprecated This method has been deprecated with no replacement
	 */
	@Override
	@Deprecated
	public Enumeration<Servlet> getServlets() {

		return (new Vector<Servlet>().elements());

	}

	/**
	 * Log the specified message.
	 *
	 * @param message The message to be logged
	 */
	@Override
	public void log(String message) {

		myLogWriter.println(message);

	}

	/**
	 * Log the specified message and exception.
	 *
	 * @param exception The exception to be logged
	 * @param message   The message to be logged
	 * @deprecated Use log(String,Throwable) instead
	 */
	@Override
	@Deprecated
	public void log(Exception exception, String message) {

		log(message, exception);

	}

	/**
	 * Log the specified message and exception.
	 *
	 * @param message   The message to be logged
	 * @param exception The exception to be logged
	 */
	@Override
	public void log(String message, Throwable exception) {

		myLogWriter.println(message);
		exception.printStackTrace(myLogWriter);

	}

	/**
	 * Remove the specified context attribute.
	 *
	 * @param name Name of the attribute to remove
	 */
	@Override
	public void removeAttribute(String name) {

		myAttributes.remove(name);

	}

	/**
	 * Set or replace the specified context attribute.
	 *
	 * @param name  Name of the context attribute to set
	 * @param value Corresponding attribute value
	 */
	@Override
	public void setAttribute(String name, Object value) {

		myAttributes.put(name, value);

	}

	@Override
	public FilterRegistration.Dynamic addFilter(String filterName,
	                                            String className) {
		return null;
	}

	@Override
	public ServletRegistration.Dynamic addServlet(String servletName,
	                                              String className) {
		return null;
	}

	@Override
	public Set<SessionTrackingMode> getDefaultSessionTrackingModes() {
		return EnumSet.noneOf(SessionTrackingMode.class);
	}

	@Override
	public Set<SessionTrackingMode> getEffectiveSessionTrackingModes() {
		return EnumSet.noneOf(SessionTrackingMode.class);
	}

	@Override
	public SessionCookieConfig getSessionCookieConfig() {
		return null;
	}

	@Override
	public void setSessionTrackingModes(
			Set<SessionTrackingMode> sessionTrackingModes) {
		// Do nothing
	}

	@Override
	public Dynamic addFilter(String filterName, Filter filter) {
		return null;
	}

	@Override
	public Dynamic addFilter(String filterName,
	                         Class<? extends Filter> filterClass) {
		return null;
	}

	@Override
	public ServletRegistration.Dynamic addServlet(String servletName,
	                                              Servlet servlet) {
		return null;
	}

	@Override
	public ServletRegistration.Dynamic addServlet(String servletName,
	                                              Class<? extends Servlet> servletClass) {
		return null;
	}

	@Override
	public <T extends Filter> T createFilter(Class<T> c)
			throws ServletException {
		return null;
	}

	@Override
	public <T extends Servlet> T createServlet(Class<T> c)
			throws ServletException {
		return null;
	}

	@Override
	public FilterRegistration getFilterRegistration(String filterName) {
		return null;
	}

	@Override
	public ServletRegistration getServletRegistration(String servletName) {
		return null;
	}

	@Override
	public boolean setInitParameter(String name, String value) {
		return myParameters.putIfAbsent(name, value) == null;
	}

	@Override
	public void addListener(Class<? extends EventListener> listenerClass) {
		// NOOP
	}

	@Override
	public void addListener(String className) {
		// NOOP
	}

	@Override
	public <T extends EventListener> void addListener(T t) {
		// NOOP
	}

	@Override
	public <T extends EventListener> T createListener(Class<T> c)
			throws ServletException {
		return null;
	}

	@Override
	public void declareRoles(String... roleNames) {
		// NOOP
	}

	@Override
	public ClassLoader getClassLoader() {
		return loader;
	}

	@Override
	public int getEffectiveMajorVersion() {
		return 3;
	}

	@Override
	public int getEffectiveMinorVersion() {
		return 0;
	}

	@Override
	public Map<String, ? extends FilterRegistration> getFilterRegistrations() {
		return null;
	}

	@Override
	public JspConfigDescriptor getJspConfigDescriptor() {
		return null;
	}

	@Override
	public Map<String, ? extends ServletRegistration> getServletRegistrations() {
		return null;
	}

}
